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Frank M Raushel - One of the best experts on this subject based on the ideXlab platform.
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atropselective hydrolysis of chiral binol phosphate esters catalyzed by the Phosphotriesterase from sphingobium sp tcm1
Biochemistry, 2020Co-Authors: Dao Feng Xiang, Tamari Narindoshvili, Frank M RaushelAbstract:The Phosphotriesterase from Sphingobium sp. TCM1 (Sb-PTE) is notable for its ability to hydrolyze a broad spectrum of organophosphate triesters, including organophosphorus flame retardants and plas...
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transition state analysis of the reaction catalyzed by the Phosphotriesterase from sphingobium sp tcm1
Biochemistry, 2019Co-Authors: Andrew N Bigley, Dao Feng Xiang, Tamari Narindoshvili, Charlie W Burgert, Alvan C Hengge, Frank M RaushelAbstract:Organophosphorus flame retardants are stable toxic compounds used in nearly all durable plastic products and are considered major emerging pollutants. The Phosphotriesterase from Sphingobium sp. TC...
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substrate profile of the Phosphotriesterase homology protein from escherichia coli
Biochemistry, 2018Co-Authors: Venkatesh V Nemmara, Steven C. Almo, Dao Feng Xiang, Alexander A Fedorov, Elena V Fedorov, Jeffrey B Bonanno, Frank M RaushelAbstract:The Phosphotriesterase homology protein (PHP) from Escherichia coli is a member of a family of proteins that is related to phosphotriestrase (PTE), a bacterial enzyme from cog1735 with unusual substrate specificity toward the hydrolysis of synthetic organic phosphates and phosphonates. PHP was cloned, purified to homogeneity, and functionally characterized. The three-dimensional structure of PHP was determined at a resolution of 1.84 A with zinc and phosphate in the active site. The protein folds as a distorted (β/α)8-barrel and possesses a binuclear metal center in the active site. The catalytic function and substrate profile of PHP were investigated using a structure-guided approach that combined bioinformatics, computational docking, organic synthesis, and steady-state enzyme kinetics. PHP was found to catalyze the hydrolysis of phosphorylated glyceryl acetates. The best substrate was 1,2-diacetyl glycerol-3-phosphate with a kcat/Km of 4.9 × 103 M–1 s–1. The presence of a phosphate group in the substra...
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an opaa enzyme mutant with increased catalytic efficiency on the nerve agents sarin soman and gp
Enzyme and Microbial Technology, 2017Co-Authors: Sue Y Bae, Frank M Raushel, James M Myslinski, Leslie R Mcmahon, J J Height, Andrew N Bigley, Steven P HarveyAbstract:The wild-type OPAA enzyme has relatively high levels of catalytic activity against several organophosphate G-type nerve agents. A series of mutants containing replacement amino acids at the OPAA Y212, V342, and I215 sites showed several fold enhanced catalytic efficiency on sarin, soman, and GP. One mutant, Y212F/V342L, showed enhanced stereospecificity on sarin and that enzyme along with a Phosphotriesterase mutant, GWT, which had the opposite stereospecificity, were used to generate enriched preparations of each sarin enantiomer. Inhibition of acetylcholinesterase by the respective enantioenriched sarin solutions subsequently provided identification of the sarin enantiomers as separated by normal phase enantioselective liquid chromatography coupled with atmospheric pressure chemical ionization-mass spectrometry.
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structure of a novel Phosphotriesterase from sphingobium sp tcm1 a familiar binuclear metal center embedded in a seven bladed β propeller protein fold
Biochemistry, 2016Co-Authors: Mark F Mabanglo, Dao Feng Xiang, Andrew N Bigley, Frank M RaushelAbstract:A novel Phosphotriesterase was recently discovered and purified from Sphingobium sp. TCM1 (Sb-PTE) and shown to catalyze the hydrolysis of a broad spectrum of organophosphate esters with a catalytic efficiency that exceeds 10(6) M(-1) s(-1) for the hydrolysis of triphenyl phosphate. The enzyme was crystallized and the three-dimensional structure determined to a resolution of 2.1 A using single-wavelength anomalous diffraction (Protein Data Bank entry 5HRM ). The enzyme adopts a seven-bladed β-propeller protein fold, and three disulfide bonds were identified between Cys-146 and Cys-242, Cys-411 and Cys-443, and Cys-542 and Cys-559. The active site of Sb-PTE contains a binuclear manganese center that is nearly identical to that of the structurally unrelated Phosphotriesterase from Pseudomonas diminuta (Pd-PTE). The two metal ions in the active site are bridged to one another by Glu-201 and a water molecule. The α-metal ion is further coordinated to the protein by interactions with His-389, His-475, and Glu-407, whereas the β-metal ion is further liganded to His-317 and His-258. Computational docking of mimics of the proposed pentavalent reaction intermediates for the hydrolysis of organophosphates was used to provide a model for the binding of chiral substrates in the active site of Sb-PTE. The most striking difference in the catalytic properties of Sb-PTE, relative to those of Pd-PTE, is the enhanced rate of hydrolysis of organophosphate esters with substantially weaker leaving groups. The structural basis for this difference in the catalytic properties between Sb-PTE and Pd-PTE, despite the nearly identical binuclear metal centers for the activation of the substrate and nucleophilic water molecule, is at present unclear.
Dao Feng Xiang - One of the best experts on this subject based on the ideXlab platform.
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atropselective hydrolysis of chiral binol phosphate esters catalyzed by the Phosphotriesterase from sphingobium sp tcm1
Biochemistry, 2020Co-Authors: Dao Feng Xiang, Tamari Narindoshvili, Frank M RaushelAbstract:The Phosphotriesterase from Sphingobium sp. TCM1 (Sb-PTE) is notable for its ability to hydrolyze a broad spectrum of organophosphate triesters, including organophosphorus flame retardants and plas...
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transition state analysis of the reaction catalyzed by the Phosphotriesterase from sphingobium sp tcm1
Biochemistry, 2019Co-Authors: Andrew N Bigley, Dao Feng Xiang, Tamari Narindoshvili, Charlie W Burgert, Alvan C Hengge, Frank M RaushelAbstract:Organophosphorus flame retardants are stable toxic compounds used in nearly all durable plastic products and are considered major emerging pollutants. The Phosphotriesterase from Sphingobium sp. TC...
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substrate profile of the Phosphotriesterase homology protein from escherichia coli
Biochemistry, 2018Co-Authors: Venkatesh V Nemmara, Steven C. Almo, Dao Feng Xiang, Alexander A Fedorov, Elena V Fedorov, Jeffrey B Bonanno, Frank M RaushelAbstract:The Phosphotriesterase homology protein (PHP) from Escherichia coli is a member of a family of proteins that is related to phosphotriestrase (PTE), a bacterial enzyme from cog1735 with unusual substrate specificity toward the hydrolysis of synthetic organic phosphates and phosphonates. PHP was cloned, purified to homogeneity, and functionally characterized. The three-dimensional structure of PHP was determined at a resolution of 1.84 A with zinc and phosphate in the active site. The protein folds as a distorted (β/α)8-barrel and possesses a binuclear metal center in the active site. The catalytic function and substrate profile of PHP were investigated using a structure-guided approach that combined bioinformatics, computational docking, organic synthesis, and steady-state enzyme kinetics. PHP was found to catalyze the hydrolysis of phosphorylated glyceryl acetates. The best substrate was 1,2-diacetyl glycerol-3-phosphate with a kcat/Km of 4.9 × 103 M–1 s–1. The presence of a phosphate group in the substra...
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structure of a novel Phosphotriesterase from sphingobium sp tcm1 a familiar binuclear metal center embedded in a seven bladed β propeller protein fold
Biochemistry, 2016Co-Authors: Mark F Mabanglo, Dao Feng Xiang, Andrew N Bigley, Frank M RaushelAbstract:A novel Phosphotriesterase was recently discovered and purified from Sphingobium sp. TCM1 (Sb-PTE) and shown to catalyze the hydrolysis of a broad spectrum of organophosphate esters with a catalytic efficiency that exceeds 10(6) M(-1) s(-1) for the hydrolysis of triphenyl phosphate. The enzyme was crystallized and the three-dimensional structure determined to a resolution of 2.1 A using single-wavelength anomalous diffraction (Protein Data Bank entry 5HRM ). The enzyme adopts a seven-bladed β-propeller protein fold, and three disulfide bonds were identified between Cys-146 and Cys-242, Cys-411 and Cys-443, and Cys-542 and Cys-559. The active site of Sb-PTE contains a binuclear manganese center that is nearly identical to that of the structurally unrelated Phosphotriesterase from Pseudomonas diminuta (Pd-PTE). The two metal ions in the active site are bridged to one another by Glu-201 and a water molecule. The α-metal ion is further coordinated to the protein by interactions with His-389, His-475, and Glu-407, whereas the β-metal ion is further liganded to His-317 and His-258. Computational docking of mimics of the proposed pentavalent reaction intermediates for the hydrolysis of organophosphates was used to provide a model for the binding of chiral substrates in the active site of Sb-PTE. The most striking difference in the catalytic properties of Sb-PTE, relative to those of Pd-PTE, is the enhanced rate of hydrolysis of organophosphate esters with substantially weaker leaving groups. The structural basis for this difference in the catalytic properties between Sb-PTE and Pd-PTE, despite the nearly identical binuclear metal centers for the activation of the substrate and nucleophilic water molecule, is at present unclear.
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chemical mechanism of the Phosphotriesterase from sphingobium sp strain tcm1 an enzyme capable of hydrolyzing organophosphate flame retardants
Journal of the American Chemical Society, 2016Co-Authors: Andrew N Bigley, Dao Feng Xiang, Zhongjie Ren, Haoran Xue, Kenneth G Hull, Daniel Romo, Frank M RaushelAbstract:The mechanism of action of the manganese-dependent Phosphotriesterase from Sphingobium sp. strain TCM1 that is capable of hydrolyzing organophosphate flame retardants was determined. The enzyme was shown to hydrolyze the RP-enantiomer of O-methyl O-cyclohexyl p-nitrophenyl thiophosphate with net inversion of configuration and without the formation of a covalent reaction intermediate. These results demonstrate that the enzyme catalyzes the hydrolysis of substrates by activation of a nucleophilic water molecule for direct attack at the phosphorus center.
Andrew N Bigley - One of the best experts on this subject based on the ideXlab platform.
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transition state analysis of the reaction catalyzed by the Phosphotriesterase from sphingobium sp tcm1
Biochemistry, 2019Co-Authors: Andrew N Bigley, Dao Feng Xiang, Tamari Narindoshvili, Charlie W Burgert, Alvan C Hengge, Frank M RaushelAbstract:Organophosphorus flame retardants are stable toxic compounds used in nearly all durable plastic products and are considered major emerging pollutants. The Phosphotriesterase from Sphingobium sp. TC...
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an opaa enzyme mutant with increased catalytic efficiency on the nerve agents sarin soman and gp
Enzyme and Microbial Technology, 2017Co-Authors: Sue Y Bae, Frank M Raushel, James M Myslinski, Leslie R Mcmahon, J J Height, Andrew N Bigley, Steven P HarveyAbstract:The wild-type OPAA enzyme has relatively high levels of catalytic activity against several organophosphate G-type nerve agents. A series of mutants containing replacement amino acids at the OPAA Y212, V342, and I215 sites showed several fold enhanced catalytic efficiency on sarin, soman, and GP. One mutant, Y212F/V342L, showed enhanced stereospecificity on sarin and that enzyme along with a Phosphotriesterase mutant, GWT, which had the opposite stereospecificity, were used to generate enriched preparations of each sarin enantiomer. Inhibition of acetylcholinesterase by the respective enantioenriched sarin solutions subsequently provided identification of the sarin enantiomers as separated by normal phase enantioselective liquid chromatography coupled with atmospheric pressure chemical ionization-mass spectrometry.
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structure of a novel Phosphotriesterase from sphingobium sp tcm1 a familiar binuclear metal center embedded in a seven bladed β propeller protein fold
Biochemistry, 2016Co-Authors: Mark F Mabanglo, Dao Feng Xiang, Andrew N Bigley, Frank M RaushelAbstract:A novel Phosphotriesterase was recently discovered and purified from Sphingobium sp. TCM1 (Sb-PTE) and shown to catalyze the hydrolysis of a broad spectrum of organophosphate esters with a catalytic efficiency that exceeds 10(6) M(-1) s(-1) for the hydrolysis of triphenyl phosphate. The enzyme was crystallized and the three-dimensional structure determined to a resolution of 2.1 A using single-wavelength anomalous diffraction (Protein Data Bank entry 5HRM ). The enzyme adopts a seven-bladed β-propeller protein fold, and three disulfide bonds were identified between Cys-146 and Cys-242, Cys-411 and Cys-443, and Cys-542 and Cys-559. The active site of Sb-PTE contains a binuclear manganese center that is nearly identical to that of the structurally unrelated Phosphotriesterase from Pseudomonas diminuta (Pd-PTE). The two metal ions in the active site are bridged to one another by Glu-201 and a water molecule. The α-metal ion is further coordinated to the protein by interactions with His-389, His-475, and Glu-407, whereas the β-metal ion is further liganded to His-317 and His-258. Computational docking of mimics of the proposed pentavalent reaction intermediates for the hydrolysis of organophosphates was used to provide a model for the binding of chiral substrates in the active site of Sb-PTE. The most striking difference in the catalytic properties of Sb-PTE, relative to those of Pd-PTE, is the enhanced rate of hydrolysis of organophosphate esters with substantially weaker leaving groups. The structural basis for this difference in the catalytic properties between Sb-PTE and Pd-PTE, despite the nearly identical binuclear metal centers for the activation of the substrate and nucleophilic water molecule, is at present unclear.
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chemical mechanism of the Phosphotriesterase from sphingobium sp strain tcm1 an enzyme capable of hydrolyzing organophosphate flame retardants
Journal of the American Chemical Society, 2016Co-Authors: Andrew N Bigley, Dao Feng Xiang, Zhongjie Ren, Haoran Xue, Kenneth G Hull, Daniel Romo, Frank M RaushelAbstract:The mechanism of action of the manganese-dependent Phosphotriesterase from Sphingobium sp. strain TCM1 that is capable of hydrolyzing organophosphate flame retardants was determined. The enzyme was shown to hydrolyze the RP-enantiomer of O-methyl O-cyclohexyl p-nitrophenyl thiophosphate with net inversion of configuration and without the formation of a covalent reaction intermediate. These results demonstrate that the enzyme catalyzes the hydrolysis of substrates by activation of a nucleophilic water molecule for direct attack at the phosphorus center.
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interrogation of the substrate profile and catalytic properties of the Phosphotriesterase from sphingobium sp strain tcm1 an enzyme capable of hydrolyzing organophosphate flame retardants and plasticizers
Biochemistry, 2015Co-Authors: Dao Feng Xiang, Andrew N Bigley, Zhongjie Ren, Haoran Xue, Kenneth G Hull, Daniel Romo, Frank M RaushelAbstract:The most familiar organophosphorus compounds are the neurotoxic insecticides and nerve agents. A related group of organophosphorus compounds, the phosphotriester plasticizers and flame retardants, has recently become widely used. Unlike the neurotoxic phosphotriesters, the plasticizers and flame retardants lack an easily hydrolyzable bond. While the hydrolysis of the neurotoxic organophosphates by Phosphotriesterase enzymes is well-known, the lack of a labile bond in the flame retardants and plasticizers renders them inert to typical Phosphotriesterases. A Phosphotriesterase from Sphingobium sp. strain TCM1 (Sb-PTE) has recently been reported to catalyze the hydrolysis of organophosphorus flame retardants. This enzyme has now been expressed in Escherichia coli, and the activity with a wide variety of organophosphorus substrates has been characterized and compared to the activity of the well-known Phosphotriesterase from Pseudomonas diminuta (Pd-PTE). Structure prediction suggests that Sb-PTE has a β-prope...
Giuseppe Manco - One of the best experts on this subject based on the ideXlab platform.
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polymeric biocatalytic membranes with immobilized thermostable Phosphotriesterase
Journal of Membrane Science, 2016Co-Authors: Giuseppe Vitola, Giuseppe Manco, Elena Porzio, Rosalinda Mazzei, Enrica Fontananova, S N Gaeta, Lidietta GiornoAbstract:Abstract In this work the catalytic performance of a mutant (named Sso Pox W263F) of the thermophilic Phosphotriesterase-like lactonase (PLL) isolated from Sulfolobus solfataricus ( Sso Pox) was reported both on free and immobilized membrane systems using as substrate the pesticide paraoxon. The single mutant Sso Pox W263F was immobilized on/into hydrophilic (Non standard grade Polyethersulphone, NGS-PES) and hydrophobic (Polyvinylidenefluoride, PVDF) membranes. Biocatalytic membrane systems able to work in liquid and vapour phase were developed aimed at decontamination of water and air, respectively. The work aimed at membranes characterization in terms of vapour and water permeability, free and immobilized enzyme catalytic and specific activity. Enzyme stability was also monitored for more than 5 months in order to evaluate the stability of developed systems. Results demonstrated that although free Sso Pox W263F showed a higher performance up to 30 days it completely loses its activity after two months. On the contrary biocatalytic membranes showed an initial loss of activity in the first days (residual specific activity of about 54%when immobilized on/into NSG-PES and 5% when immobilized on/into PVDF) but any change in stability during more than 5 months. In the case of PVDF, the residual specific activity can be enhanced tuning the amount of immobilized Sso Pox W263F, in fact it was demonstrated that there is a trade-off between amount of immobilized enzyme and catalytic performance.
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Crystallization and preliminary X-ray diffraction analysis of the hyperthermophilic Sulfolobus solfataricus Phosphotriesterase.
Acta Crystallographica Section F Structural Biology and Crystallization Communications, 2007Co-Authors: Mikael Elias, Mose Rossi, Giuseppe Manco, Jérôme Dupuy, Luigia Merone, Claude Lecomte, Patrick Masson, Eric ChabrièreAbstract:Organophosphates constitute the largest class of insecticides used worldwide and some of them are potent nerve agents. Consequently, organophosphate-degrading enzymes are of paramount interest as they could be used as bioscavengers and biodecontaminants. Phosphotriesterases (PTEs) are capable of hydrolyzing these toxic compounds with high efficiency. A distant and hyperthermophilic representative of the PTE family was cloned from the archeon Sulfolobus solfataricus MT4, overexpressed in Escherichia coli and crystallized; the crystals diffracted to 2.54 A resolution. Owing to its exceptional thermostability, this PTE may be an excellent candidate for obtaining an efficient organophosphate biodecontaminant. Here, the crystallization conditions and data collection for the hyperthermophilic S. solfataricus PTE are reported.
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a new Phosphotriesterase from sulfolobus acidocaldarius and its comparison with the homologue from sulfolobus solfataricus
Biochimie, 2007Co-Authors: Elena Porzio, Mose Rossi, Luigia Merone, Luigi Mandrich, Giuseppe MancoAbstract:Abstract The Phosphotriesterase PTE, identified in the soil bacterium Pseudomonas diminuta, is thought to have evolved in the last several decades to degrade the pesticide paraoxon with proficiency approaching the limit of substrate diffusion (kcat/KM of 4 × 107 M−1 s−1). It belongs to the amidohydrolase superfamily, but its evolutionary origin remains obscure. The enzyme has important potentiality in the field of the organophosphate decontamination. Recently we reported on the characterization of an archaeal member of the amidohydrolase superfamily, namely Sulfolobus solfataricus, showing low but significant and extremely thermostable paraoxonase activity (kcat/KM of 4 × 103 M−1 s−1). Looking for other thermostable Phosphotriesterases we assayed, among others, crude extracts of Sulfolobus acidocaldarius and detected activity. Since the genome of S. acidocaldarius has been recently reported, we identified there an open reading frame highly related to the S. solfataricus enzyme. The gene was cloned, the protein overexpressed in Escherichia coli, purified, and proven to have paraoxonase activity. A comparative analysis detected some significant differences between the two archaeal enzymes.
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the latent promiscuity of newly identified microbial lactonases is linked to a recently diverged Phosphotriesterase
Biochemistry, 2006Co-Authors: Livnat Afriat, Giuseppe Manco, Cintia Roodveldt, Dan S TawfikAbstract:In essence, evolutionary processes occur gradually, while maintaining fitness throughout. Along this line, it has been proposed that the ability of a progenitor to promiscuously catalyze a low level of the evolving activity could facilitate the divergence of a new function by providing an immediate selective advantage. To directly establish a role for promiscuity in the divergence of natural enzymes, we attempted to trace the origins of a bacterial Phosphotriesterase (PTE), an enzyme thought to have evolved for the purpose of degradation of a synthetic insecticide introduced in the 20th century. We surmised that PTE's promiscuous lactonase activity may be a vestige of its progenitor and tested homologues annotated as "putative PTEs" for lactonase and Phosphotriesterase activity. We identified three genes that define a new group of microbial lactonases dubbed PTE-like lactonases (PLLs). These enzymes proficiently hydrolyze various lactones, and in particular quorum-sensing N-acyl homoserine lactones (AHLs), and exhibit much lower promiscuous Phosphotriesterase activities. PLLs share key sequence and active site features with PTE and differ primarily by an insertion in one surface loop. Given their biochemical and biological function, PLLs are likely to have existed for many millions of years. PTE could have therefore evolved from a member of the PLL family while utilizing its latent promiscuous paraoxonase activity as an essential starting point.
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a thermostable Phosphotriesterase from the archaeon sulfolobus solfataricus cloning overexpression and properties
Extremophiles, 2005Co-Authors: Luigia Merone, Mose Rossi, Luigi Mandrich, Giuseppe MancoAbstract:A new gene from the hyperthermophilic archaeon Sulfolobus solfataricus MT4, coding for a putative protein reported to show sequence identity with the Phosphotriesterase-related protein family (PHP), was cloned by means of the polymerase chain reaction from the S. solfataricus genomic DNA. In order to analyse the biochemical properties of the protein an overexpression system in Escherichia coli was established. The recombinant protein, expressed in soluble form at 5 mg/l of E. coli culture, was purified to homogeneity and characterized. In contrast with its mesophilic E. coli counterpart that was devoid of any tested activity, the S. solfataricus enzyme was demonstrated to have a low paraoxonase activity. This activity was dependent from metal cations with Co2+, Mg2+ and Ni2+ being the most effective and was thermophilic and thermostable. The enzyme was inactivated with EDTA and o-phenantroline. A reported inhibitor for Pseudomonas putida Phosphotriesterase (PTE) had no effect on the S. solfataricus paraoxonase. The importance of a stable paraoxonase for detoxification of chemical warfare agents and agricultural pesticides will be discussed.
Thierry Noguer - One of the best experts on this subject based on the ideXlab platform.
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Selective spectrophotometric detection of insecticides using cholinesterases, Phosphotriesterase and chemometric analysis
Enzyme and Microbial Technology, 2010Co-Authors: Amina Rhouati, Georges Istamboulie, Jean Louis Marty, Montserrat Cortina-puig, Thierry NoguerAbstract:Enzyme spectrophotometric assays based on acetylcholinesterase (AChE) inhibition were used in combination with Artificial Neural Network (ANN) chemometric analysis for the resolution of pesticides mixtures of chlorpyriphos, dichlorvos and carbofuran. Electric eel (EE) AChE and the recombinant B394-AChE from Drosophila melanogaster were selected due to their different sensitivities to insecticides. These enzymes were used in association with Phosphotriesterase (PTE), an enzyme allowing to discriminate between organophosphate and carbamate insecticides. The combined response of three enzymes systems composed of EE-AChE, EE-AChE + PTE, and B394-AChE + PTE was modelled by means of ANN. Specifically, an ANN was constructed where the structure providing the best modelling was a single hidden layer containing four neurons. To prove the concept, a study to resolve pesticide mixtures was done with spectrophotometric measurements. Finally the developed system was successfully applied to the determination of carbofuran, CPO and dichlorvos pesticides in real water samples.
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biosensor controlled degradation of chlorpyrifos and chlorfenvinfos using a Phosphotriesterase based detoxification column
Chemosphere, 2010Co-Authors: Georges Istamboulie, Jean Louis Marty, Didier Fournier, Romain Durbiano, Thierry NoguerAbstract:Abstract This works presents the development of a detoxification system based on bacterial Phosphotriesterase (PTE) for the degradation of organophosphate (OP) insecticides in water. PTE was immobilised on an activated agarose gel via covalent coupling. Two different OPs were studied, chlorpyrifos and chlorfenvinfos, due to their importance in the field of water policy. The efficiency of insecticide degradation was controlled using a highly sensitive biosensor allowing the detection of OP concentration as low as 0.004 μg L−1. Under optimum conditions, it was shown that a column incorporating 500 IU of PTE was suitable for the detoxification of solutions containing either isolated pesticides or pesticides mixtures, even at concentrations higher than authorized limits. Finally, the method was shown to be adapted to the decontamination of real samples of pesticides with concentrations up to 20 μg L−1.
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the use of artificial neural networks for the selective detection of two organophosphate insecticides chlorpyrifos and chlorfenvinfos
Talanta, 2009Co-Authors: Georges Istamboulie, Jean Louis Marty, Montserrat Cortinapuig, Thierry NoguerAbstract:Amperometric acetylcholinesterase (AChE) biosensors have been developed to resolve mixtures of chlorpyrifos oxon (CPO) and chlorfenvinfos (CFV) pesticides. Three different biosensors were built using the wild type from electric eel (EE), the genetically modified Drosophila melanogaster AChE B394 and B394 co-immobilized with a Phosphotriesterase (PTE). Artificial Neural Networks (ANNs) were used to model the combined response of the two pesticides. Specifically two different ANNs were constructed. The first one was used to model the combined response of B394 + PTE and EE biosensors and was applied when the concentration of CPO was high and the other, modelling the combined response of B394 + PTE and B394 biosensors, was applied with low concentrations of CPO. In both cases, good prediction ability was obtained with correlation coefficients better than 0.986 when the obtained values were compared with those expected for a set of six external test samples not used for training.
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Phosphotriesterase a complementary tool for the selective detection of two organophosphate insecticides chlorpyrifos and chlorfenvinfos
Talanta, 2009Co-Authors: Georges Istamboulie, Jean Louis Marty, Didier Fournier, Thierry NoguerAbstract:This work shows the possibility of combining the high sensitivity of genetically-modified Drosophila melanogaster acetylcholinesterase (B394) with the ability of Phosphotriesterase (PTE) to hydrolyse organophosphate compounds, in the aim of developing a biosensor selective to two insecticides of interest: chlorpyrifos and chlorfenvinfos. The studies clearly demonstrate that chlorfenvinfos is a substrate that acts as competitive inhibitor of PTE, therefore preventing the efficient hydrolysis of other pesticides, including chlorpyrifos. A bi-enzymatic sensor was designed by immobilizing both B394 and PTE in a polyvinylalcohol matrix. The sensor was shown to be able to discriminate between chlorpyrifos and chlorfenvinfos inhibitions.
